Lots of stuff has to be done
for the vehicle to prepare it for the TDI motor!

Preparing the fuel system:

Step 1

0h15m

Drain the fuel tank of all
gasoline.

This can be done by supplying the gasoline fuel pump 12V until
the tank runs dry. The fuel pump can remove more fuel than
just draining the tank.

Step 2

1h00m

Remove filler neck restrictor.

This is done by removing the filler tube between the tank and
the filler cap. The 'neck' of the filler tube is crimped
on to the plastic filler tube. Use a hand held grinder to
cut the crimp. Once the tube is pulled out of the neck,
the restrictor can be removed. Install the neck again and
use a hose clamp to secure it in place. Reinstall the
fuller tube.

Step 3

0h15m

Rinse the fuel tank.

This is done by putting about 5L of Diesel fuel into the
tank. Use the gasoline pump to remove all the Diesel
from the tank.

Step 4

1h00m

Remove fuel pump and fuel pump
wiring.

Replace the smaller fuel line between the pump and the
original motor and the return line as over time they get
brittle and can leak. Make sure there is enough hose in
the engine compartment to easily reach the front right corner
where you will locate the Diesel fuel filter / water separator.
A common brass 1/8" to 1/4" barbed fitting can
bridge the new hose that is installed and the original hose
that came from the tank. Make sure you cover the ends of
the hoses so that they do not get contaminated with dirt.

Suggestion: Now is a good time to put about 10L of Diesel
fuel in the tank.

2h30m

Total time for preparing the fuel system.

Preparing the electrical system:

Step 1

0h15m

Remove the unnecessary wires from
the engine compartment.

Remove the fuel pump / ECU relay
box

There should be only a hand full of wire left in the engine
compartment. The BK and GN wires that went to the
coil. The Y/R wire that went to the coolant temperature
sensor. The BL/BK and Y wires to the oil pressure
switches. The R and R/BK wires that went to the relay
box. The BK and BR wires that went to the original
wasserboxer crank case vent heater.

Step 2

1h00m

Install a pin switch on the brake
pedal and the clutch pedal

These switches should 'on' when the pedals are at rest and 'off'
as soon as you begin to press the pedal. These switches
are used for the cruise control and by the ECU.

Caution: The AHU and ALH engines use different types of
signal logic for the pedals! Please follow the
instructions with your wire harness as to if you are to connect
12V or ground to one side of the switch.

Step 3

0h45m

Run a 10 conductor, shielded cable from the engine
compartment the instrument cluster. Printer cable or CAT5
works well.

Malfunction Indicator Light -
Red LED to be installed in instrument cluster.

Glow Plug Light - Yellow LED to
be installed in instrument cluster.

Brake Pedal Switch - connect to
switch installed in step 2

Clutch Pedal Switch - connect
to switch installed in step 2

K [OBD line] - have it so that
it reaches under the ash tray where the OBD connector will be
installed.

CAN Bus - High [OBD line - ALH
only] - have it so that it reaches under the ash tray
where the OBD connector will be installed.

CAN Bus - Low [OBD line - ALH
only] - have it so that it reaches under the ash tray
where the OBD connector will be installed.

Spare - gotta have a spare wire
right!? - Can be used for cruise control too!

Spare - gotta have a spare wire
right!? - Can be used for cruise control too!

Spare - gotta have a spare wire
right!? - Can be used for cruise control too!

Run a 2rd CAT5 cable from he
engine compartment to the instrument cluster if you are using
the ALH style throttle pedal. Can be used for cruise control
too!

Suggestion: If you are going to install an oil pressure
gauge, EGT gauge or other accessories that require cockpit
monitoring there will be enough spare wires in the CAT5 cables
to accommodate this. Remember to use cable like this only
for signals and not for anything that requires any current.

Step 4

1h00m

Install a VDO tachometer from a
1985 to 1992 Diesel Jetta or Golf in place of your gasoline
tachometer.

Four out of five Vanagon tachometers are not sensitive enough to
use the tachometer signal from the TDI ECU. We recommend
installing the above tachometer and using the signal from the W
terminal to drive it. More than likely it will need some
adjusting, there is a small adjusting potentiometer at the rear
of the tachometer. The Vanagon fuel gauges and coolant
temperature gauges will transfer directly over to the new
tachometer.